Laminated mats with closed and strengthened core layer

Abstract

A laminated mat for use as the temporary surface at a construction site or roadway leading thereto. This mat includes at least three layers of boards in a top layer, at least one core layer and a base layer. Preferably, each layer is rectangular. The top and base layers each include a plurality of parallel boards of substantially equal length that are made of oak or other hardwoods, or of plastic or elastomeric materials. The core layer includes a plurality of parallel boards of substantially equal length that are made of chemically treated softwood, encapsulated softwood, or of plastic or elastomeric materials, with the boards arranged to be perpendicular to the boards of the top layer, and configured so that adjacent boards in the core layer engage, contact and abut each other to minimize or eliminate space between adjacent boards to improve the strength of the core layer.

What is claimed is: 
     
       1. A laminated mat for use as the temporary surface at a construction site or roadway leading thereto and adapted for supporting construction equipment, the mat including at least three layers of boards comprising:
 a rectangular top layer having a first end and an opposed second end, with the top layer base comprising a plurality of parallel boards of substantially equal length that are spaced from each other and are made of oak or other hardwoods, engineered wood or of plastic or elastomeric materials; 
 a rectangular core layer comprising a plurality of parallel boards of substantially equal length that are made of chemically treated softwood, encapsulated softwood, or of plastic or elastomeric materials, with the boards extending between the first and second ends of the top layer, arranged to be perpendicular to the boards of the top layer, and having sides configured so that adjacent boards in the core layer engage, contact and abut each other with tolerances of 0.1 inches or less to minimize or eliminate space between adjacent boards to improve the strength of the core layer, wherein the boards of the core layer have sides that are perpendicular to upper and lower surfaces of the boards to facilitate abutting and complete side contact between adjacent boards; and 
 a rectangular base layer having a first end and an opposed second end which are aligned with the first and second ends of the top layer, with the base layer comprising a plurality of parallel boards of substantially equal length that are spaced from each other and are made of oak or other hardwoods, engineered wood or of plastic or elastomeric materials, with the boards of the base layer oriented parallel to the boards of the top layer and perpendicular to the boards of the core layer; 
 wherein at least two or three boards of the base layer are longitudinally offset to the other boards to form at a first end of the mat having two or three protruding board ends and to correspondingly form at a second end of the mat two or three open slots such that the protruding board ends of one mat can engage the open slots of a similarly configured longitudinally adjacent mat to interlock the mats together to form the temporary surface at the construction site; 
 wherein the mat has a width of between about 4 feet and about 12 feet and a length of between about 10 and about 60 feet, wherein the boards are removably attached together by bolting or other fasteners, and wherein all boards in the mat have a thickness of between about 1 and about 4 inches and a width of between about 4 and about 16 inches, while the boards in the top and base layers have a length that is the same as the length of the mat. 
 
     
     
       2. The laminated mat of  claim 1  wherein the boards of the core layer have sides that are cut, planed, or molded to facilitate abutting and complete side contact between adjacent boards. 
     
     
       3. The laminated mat of  claim 1  wherein adjacent boards of the core layer have sides that are adhered together by an adhesive. 
     
     
       4. The laminated mat of  claim 1  wherein each board in the core layer is rectangular and is made of treated pine that is pressure treated with chemical preservatives that resist rot, decay and termites and wherein the top and base layers include rectangular boards made of oak. 
     
     
       5. The laminated mat of  claim 1  wherein each board in the core layer is made of recycled plastic material comprising rice hulls and polyethylene and wherein the top and base layers include rectangular boards made of oak. 
     
     
       6. The laminated mat of  claim 1  wherein each board in the core layer is rectangular and is made of treated pine that is pressure treated with one or more chemical preservatives that resist rot, decay and termites and wherein the top and base layers include rectangular boards made of recycled plastic material comprising a polymer and rice hulls or recycled plastic carpet fibers. 
     
     
       7. The laminated mat of  claim 1  wherein the boards in the top and base layers each have a thickness of between 1.5 and 2.5 inches, a width of between 6 and 9 inches and a spacing between adjacent boards of between 1.5 and 2.5 inches, while the boards in the core layer have a thickness between 1.5 and 2.5 inches and a width of between 8 and 14 inches. 
     
     
       8. The laminated mat of  claim 7 , wherein each board in the top and base layers has the same dimensions, each board in the core layer has the same dimensions, and the width of the boards in the core layer is about 25 to 70% greater than the width of the boards in the top and base layers. 
     
     
       9. The laminated mat of  claim 8  having a width of about 8 feet and a length of about 12 to about 16 feet, with eleven boards in each of the top and base layers with the boards having a width of 7 to 8 inches, and with 12 to 24 boards in the core layer, each having a length of about 8 feet and a width of 8 to 12 inches. 
     
     
       10. The laminated mat of  claim 8  having a width of about 8 feet and a length of about 12 to about 16 feet, with seven boards in each of the top and base layers with the boards having a width of 12 to 15 inches, and with 12 to 24 boards in the core layer each having a length of about 8 feet and a width of 8 to 12 inches. 
     
     
       11. The laminated mat of  claim 1  which further comprises one or more additional core layers comprising a plurality of parallel boards of substantially equal length that are made of chemically treated softwood, encapsulated softwood, or of plastic or elastomeric materials, with the boards extending between the first and second ends of the top layer, arranged to be parallel or perpendicular to the boards of the core layer, and configured so that adjacent boards in the core layer engage, contact and abut each other to minimize or eliminate space between adjacent boards to improve the strength of the core layer. 
     
     
       12. The laminated mat of  claim 10  wherein two additional core layers are provided with the boards in a first additional core layer arranged to be perpendicular to the boards of the core layer and with the boards in a second additional layer arranged to be parallel to the boards of the core layer with the parallel boards being located between the core layers that include the perpendicular boards. 
     
     
       13. The laminated mat of  claim 1  further comprising one or more lifting elements attached to one or more of the boards of the top or base layers. 
     
     
       14. A method for prolonging the service life of a laminated mat that has wood components, which comprises: configuring the mat to have a reusable core layer that provides strength and rigidity to the mat, wherein the core layer is provided as an integral unit of a plurality of parallel boards of substantially equal length that are made of chemically treated softwood, encapsulated softwood, or of plastic or elastomeric materials, with the boards extending between the first and second ends of the top layer, arranged to be perpendicular to the boards of the top layer, and having sides configured so that adjacent boards in the core layer engage, contact and abut each other with tolerances of 0.1 inches or less to minimize or eliminate space between adjacent boards to improve the strength of the core layer, and with the boards of the core layer having sides that are perpendicular to upper and lower surfaces of the boards to facilitate abutting and complete side contact between adjacent boards; providing top and base layers attached to the core layer directly or indirectly through additional layers, with the top and base layers forming upper and lower surfaces of the mat, wherein the top and base layers each comprises a plurality of parallel boards of substantially equal length that are spaced from each other and are made of oak or other hardwoods, or of plastic or elastomeric materials, and wherein all boards in the mat have a thickness of between about 1 and about 4 inches and a width of between about 4 and about 16 inches; removably attaching the boards of the top and base layers to the reusable core layer by a bolting arrangement; and renewing the mat by replacing boards of the top and base layers that are damaged or deteriorated during use by removing one or more o:f the damaged or deteriorated boards while reusing the core layer to form a renewed mat having the core layer with one or more replaced boards in the top or base layers, thus providing a prolonged service life for the mat. 
     
     
       15. The method of  claim 14 , wherein the boards of the top or base layers are removable by loosening the bolting arrangement and by attaching the replacement boards to the core layer using the same bolting arrangement. 
     
     
       16. A laminated mat for use as the temporary surface at a construction site or roadway leading thereto and adapted for supporting construction equipment, the mat including at least three layers of boards comprising:
 a rectangular top layer having a first end and an opposed second end, with the top layer base comprising a plurality of parallel boards of substantially equal length that are spaced from each other and are made of oak or other hardwoods, engineered wood or of plastic or elastomeric materials; 
 a rectangular core layer comprising a plurality of parallel boards of substantially equal length that are made of chemically treated softwood, encapsulated softwood, or of plastic or elastomeric materials, with the boards extending between the first and second ends of the top layer, arranged to be perpendicular to the boards of the top layer, and having sides configured so that adjacent boards in the core layer engage, contact and abut each other with tolerances of 0.1 inches or less to minimize or eliminate space between adjacent boards to improve the strength of the core layer; and 
 a rectangular base layer having a first end and an opposed second end which are aligned with the first and second ends of the top layer, with the base layer comprising a plurality of parallel boards of substantially equal length that are spaced from each other and are made of oak or other hardwoods, engineered wood or of plastic or elastomeric materials, with the boards of the base layer oriented parallel to the boards of the top layer and perpendicular to the boards of the core layer; 
 wherein the boards in the top and base layers each have a thickness of between 1.5 and 2.5 inches, a width of between 6 and 9 inches and a spacing between adjacent boards of between 1.5 and 2.5 inches, while the boards in the core layer have a thickness between 1.5 and 2.5 inches, a width of between 8 and 14 inches and complete side to side contact with any space between them being sufficient to prevent moisture, mud or debris from entering between the boards, with the boards of the core layer having sides that are perpendicular to upper and lower surfaces of the boards to facilitate abutting and complete side contact between adjacent boards; 
 wherein at least two or three boards of the base layer are longitudinally offset to the other boards to form at a first end of the mat having two or three protruding board ends and to correspondingly form at a second end of the mat two or three open slots such that the protruding board ends of one mat can engage the open slots of a similarly configured longitudinally adjacent mat to interlock the mats together to form the temporary surface at the construction site; and 
 wherein the mat has a width of between about 4 feet and about 12 feet and a length of between about 10 and about 60 feet, wherein the boards are removably attached together by bolting or other fasteners. 
 
     
     
       17. The laminated mat of  claim 16  having a width of about 8 feet and a length of about 12 to about 16 feet, wherein each board in the top and base layers has the same dimensions, each board in the core layer has the same dimensions, and the width of the boards in the core layer is greater than the width of the boards in the top and base layers, with either eleven boards in each of the top and base layers with the boards having a width of 7 to 8 inches, and with 12 to 24 boards in the core layer, each having a length of about 8 feet and a width of 8 to 12 inches, or with seven boards in each of the top and base layers with the boards having a width of 12 to 15 inches, and with 12 to 24 boards in the core layer each having a length of about 8 feet and a width of 8 to 12 inches. 
     
     
       18. A laminated mat for use as the temporary surface at a construction site or roadway leading thereto and adapted for supporting construction equipment, the mat including at least three layers of boards comprising:
 a rectangular top layer having a first end and an opposed second end, with the top layer base comprising a plurality of parallel boards of substantially equal length that are spaced from each other and are made of oak or other hardwoods, engineered wood or of plastic or elastomeric materials; 
 a rectangular core layer comprising a plurality of parallel boards of substantially equal length that are made of chemically treated softwood, encapsulated softwood, or of plastic or elastomeric materials, with the boards extending between the first and second ends of the top layer, arranged to be perpendicular to the boards of the top layer, and having sides configured so that adjacent boards in the core layer engage, contact and abut each other with tolerances of 0.1 inches or less to minimize or eliminate space between adjacent boards to improve the strength of the core layer, wherein adjacent boards of the core layer have sides forming angles that are other than 90 degrees with respect to upper and lower board surfaces to facilitate abutting and complete side contact of adjacent boards, with boards of the core layer of the mat optionally having 90 degree sides at the first and second ends of the mat; and 
 a rectangular base layer having a first end and an opposed second end which are aligned with the first and second ends of the top layer, with the base layer comprising a plurality of parallel boards of substantially equal length that are spaced from each other and are made of oak or other hardwoods, engineered wood or of plastic or elastomeric materials, with the boards of the base layer oriented parallel to the boards of the top layer and perpendicular to the boards of the core layer; 
 wherein at least two or three boards of the base layer are longitudinally offset to the other boards to form at a first end of the mat having two or three protruding board ends and to correspondingly form at a second end of the mat two or three open slots such that the protruding board ends of one mat can engage the open slots of a similarly configured longitudinally adjacent mat to interlock the mats together to form the temporary surface at the construction site; 
 wherein the mat has a width of between about 4 feet and about 12 feet and a length of between about 10 and about 60 feet, wherein the boards are removably attached together by bolting or other fasteners, and wherein all boards in the mat have a thickness of between about 1 and about 4 inches and a width of between about 4 and about 16 inches, while the boards in the top and base layers have a length that is the same as the length of the mat. 
 
     
     
       19. The laminated mat of  claim 18 , wherein the boards in the top and base layers each have a thickness of between 1.5 and 2.5 inches, a width of between 6 and 9 inches and a spacing between adjacent boards of between 1.5 and 2.5 inches, while the boards in the core layer have a thickness between 1.5 and 2.5 inches, a width of between 8 and 14 inches and complete side to side contact with any space between them being sufficient to prevent moisture, mud or debris from entering between the boards, with the boards of the core layer having sides that are perpendicular to upper and lower surfaces of the boards to facilitate abutting and complete side contact between adjacent boards. 
     
     
       20. The laminated mat of  claim 19  having a width of about 8 feet and a length of about 12 to about 16 feet, wherein each board in the top and base layers has the same dimensions, each board in the core layer has the same dimensions, and the width of the boards in the core layer is greater than the width of the boards in the top and base layers, with either eleven boards in each of the top and base layers with the boards having a width of 7 to 8 inches, and with 12 to 24 boards in the core layer, each having a length of about 8 feet and a width of 8 to 12 inches, or with seven boards in each of the top and base layers with the boards having a width of 12 to 15 inches, and with 12 to 24 boards in the core layer each having a length of about 8 feet and a width of 8 to 12 inches.